Dehydration Of Ethanol To Ethylene Over Metal Ions Modified HZSM-5

Due to the petroleum emergence of rising demand and decreasing supply,the price of petroleum was unavoidably increasing.Besides,the petroleum-based industry has already caused serious contamination to the global environment.As a result,a new route to substitute for the traditional chemical industry is cried for,especially in the production of ethylene,one of the most important platform compounds in the world.Nowadays much work has been done in this field.The focus is using renewable biomass as a raw material to produce ethanol,which is then converted to ethylene by chemical means.This paper concerned the dehydration of ethanol to ethylene over metal ions modified HZSM-5.In order to compare the dehydrating activity of HZSM-5 modified by different metals,a series of catalysts were prepared by both normal ion-exchange method and impregnation method.The metals for ion-exchange were Fe,Mn and Co.The results showed that Co-HZSM-5 had better performances in dehydration of ethanol.Under 493K, the best ethanol conversion of 99.67%and ethylene selectivity of 99.32%were obtained when WHSV and ethanol volume fraction were 2.5h^-1 and 60%respectively.Also,the influences of modified HZSM-5 using impregnation method with Mg,Ca, Sr,Ba,Mn,Fe,Co,Zn,Zr,Cd,La and Ce,were investigated in details.The results indicated that 0.5%Sr/HZSM-5,1.0%Mn/HZSM-5,1.0%～2.0%Zr/HZSM-5, 1.0%La/HZSM-5,0.5%Sr-0.25%La/HZSM-5,0.5%Sr-0.5%La/HZSM-5, 0.5%Sr-1.0%La/HZSM-5 and 0.25%Sr-1.0%La/HZSM-5 all had better performances in dehydration of ethanol.Under 493K,the best ethanol conversion of more than 98.00%and ethylene selectivity of more than 98.00%were obtained when WHSV and ethanol quality fraction were 2.5h^-1 and 50%respectively.